The present invention concerns the field of cosmetology, in particular cutaneous and capillary applications, and relates to the use of at least one protein fraction extracted from Hibiscus esculentus and to a composition containing at least one such extract.
The Hibiscus esculentus (Abelmoshus esculentus or Okra from the Malvaceae family) is a plant of African origin introduced into the United States and East Indies under the Spanish name of gumbo. It is one of the botanical species which has been cultivated for its pods for more than 2,000 years.
Okra grows in numerous regions of the world such as India, Malaysia, the Philippines, America (Mid-West), Mediterranean regions, Africa and, more generally, in tropical regions.
The fruits (pods) which are eaten young as vegetables are long, green and tapering; they have a delicate flavour and a mucilaginous internal texture.
Apart from the pods, which are of interest on account of the gum which they contain, research has also been carried out on the seeds of Hibiscus esculentus in order to study their potential as a new source of proteins.
To this end, the chemical composition of the whole seed of different varieties of okra (outer skin plus endosperm) has been determined.
Similarly, the properties (protein solubility, amino acid composition, emulsification capacity, foaming capacity, nutritional value) of various products obtained from the seeds (whole flour prepared from skinned seeds, delipidated flour, concentrate and protein isolate) have been studied for food purposes (see, for example, Bryant L A, Montecalvo J, Morey K S, Loy B: xe2x80x9cProcessing, functional and nutritional properties of okra seed productsxe2x80x9d, Journal of food science, vol. 53, No. 3, 818-816).
Okra seed mainly contains the following substances in % by weight, relative to the dry material:
17.7 to 21.8% of proteins
14.7 to 20.06% of lipids
4.33 to 4.62% of ash
6.84 to 7.92% of water
0.0032% of gossypol,
and, in particular, traces of the following substances:
(See Karakoltsidis P A, Constantidines S M: xe2x80x9cokra seed: a new protein sourcexe2x80x9d, J. Agric Food Chem., 1975, 23 No. 6, 1204-1207/Wandawi A L: xe2x80x9cChemical composition of seeds of two okra cultivars Abelmoschus esculentusxe2x80x9d, Journal of agricultural and food chemistry, 1983, 31 No. 6, 1355-1358).
The amino acid composition of concentrated Hibiscus esculentus seed proteins or protein isolates resembles that of soya proteins and is close to that of casein (see table below).
With regard to the casein, close contents of threonine, serine, glutamic acid, valine, isoleucine, leucine, phenylalanine, lysine and histidine are noted in particular.
The various aforementioned studies therefore demonstrate the value of Hibiscus esculentus seeds as potential sources of proteins from a food point of view.
Furthermore, the use for dermatological purposes of a viscous liquid product obtained by hot extraction and/or extraction under pressure from the fruits of Hibiscus esculentus (FR-A-2 679 443) as well as the use of a powdered material composed of polysaccharide extracted from immature Hibiscus esculentus seeds in a cosmetic product (JP-A-57/199969) are also known.
Now the inventors have found that it was possible to use extracts of Hibiscus esculentus seeds directly in cosmetics and that the use of at least one preferably soluble protein fraction extracted from Hibiscus esculentus or okra seeds, in particular as a substitute for casein, in a cosmetic composition or product yielded a composition or product having surprising and advantageous specific properties.
A strong cellular nutritive power, a smoothing and biofilm-forming effect, conditioning, restructuring and repairing effects as well as anti-irritant, light-protecting, soothing and cutaneous anti-ageing effects have thus been found.
The aforementioned extracts can be used not only for skin care and hygiene applications (products for the face or for the body, day or night products, solar products, anti-wrinkle hygiene products, slimming products), but also in the field of hair care and hygiene (lotions or shampoos; creams; mousses; protective products, repairing products, softeners, film-forming agents and light protectors; perming and colouring products).
Proteins can be prepared by conventional methods of extraction of vegetable proteins and preparation of protein concentrates or isolates known to a person skilled in the art and described, in particular, in the aforementioned article by Bryant L A, Montecalvo J, Morey K S and Loy B.
The raw material consists of Hibiscus esculentus seeds or seed flour (protein content=21.6 relative to the dry material).
The flour thus obtained may be delipidated by extraction in hexane at 45xc2x0 C. (advantageously 3 successive extractions).
The oil yield is 16.2 to 23.9% by weight, depending on whether the starting material is a whole seed flour or a flour from seeds partially freed of the outer skins or shells by sifting.
The delipidated flours partially freed of the seed shells contain between 37 and 44% by weight of proteins (Nxc3x976.25).
Various processes for obtaining and preparing extracts of Hibiscus esculentus or okra seeds will be described hereinafter by way of illustrative, non-limiting examples.
100 g of non-delipidated enriched flour (partially freed of the shell waste) in one liter of the following media:
distilled water,
distilled water containing 1 g/l of NaCl,
distilled water containing 5 g/l of NaCl,
distilled water containing 10 g/l of NaCl
are added.
After stirring for 15 minutes, the pH of the solution is adjusted to 9 with NaOH 4 N.
Extraction is carried out for one and a half hours at ambient temperature while keeping the pH at 9.
After centrifugation, the upper lipidic layer is removed and the aqueous supernatant liquid is collected.
The golden yellow supernatant liquid is adjusted to pH=7.5 then filtered to 0.22 xcexcm; it is noted that the higher the salt content of the solvent, the easier filtration is.
The protein content of the filtrate is determined by the biuret method. The supernatant liquids remain opalescent.
The following results are obtained:
25 g of enriched delipidated flour (freed from shell debris) are added in 250 ml of distilled water containing 5 g/l of sodium chloride.
After stirring for 15 minutes, the pH of the solution is adjusted to the following pH according to the test: 6-6.5-7-7.5.
Extraction is carried out for one hour at ambient temperature.
After centrifugation, the supernatant liquid is recovered, then filtered over 5 xcexcm.
The following results are obtained:
25 g of enriched delipidated flour are added in 250 ml of distilled water containing 5 g/l of sodium chloride.
The pH of the solution is adjusted to 8 after stirring for 15 minutes.
Extraction is carried out for 6 hours at ambient temperature.
After centrifugation, the supernatant liquid is recovered and the pH adjusted to 7.5, then the solution is filtered over 5 xcexcm.
The following results are obtained:
25 g of enriched delipidated flour are added in 250 ml of distilled water containing 5 g/l of sodium chloride.
After stirring for 15 minutes, the pH of the solution is adjusted to pH 7.5.
Extraction is carried out for 6 hours at 45xc2x0 C.
After centrifugation, the supernatant liquid is recovered, its pH is adjusted to 7.5 then the solution is filtered over 5 xcexcm.
The following results are obtained:
300 g enriched delipidated flour are added in 3 l of distilled water containing 5 g/l of sodium chloride.
After stirring for 15 minutes, the pH of the solution is adjusted to pH 7.5.
Extraction is carried out for 2 hours at 50xc2x0 C.
After centrifugation, the supernatant is recovered then filtered over 5 xcexcm.
The following results are obtained:
Biuret proteins: 13.7 g/l
Kjeldahl proteins: 14.6 g/l
One liter supernatant liquid is removed and its pH is adjusted to 4.5 using 4N sulphuric acid.
After 30 minutes of stirring, the solution is centrifuged and the precipitate is collected, then washed with water at pH 4.5. It is then freeze-dried: a powder of which the protein content is 85.3% by weight is obtained.
600 g of enriched delipidated flour in 6 liters of distilled water containing 5 g/l of NaCl are added while stirring in a thermostatically controller reactor. The pH measured is adjusted to 7.5.
The solution is pumped into an ultrasonic tube with an integral passage by means of a peristaltic pump (ultrasonic power 600 Wxe2x80x94frequency 20,000 Hz), the flow rate being 60 l/h.
Two discontinuous passages by successive charges are produced (the extract is collected after passage in the ultrasonic tube in a second reactor).
After centrifugation, then filtration over 5 xcexcm, the following results are obtained:
proteins from the extract after the first passage: 14.2 g/l
proteins from the extract after the second passage: 15.2 g/l
300 g of enriched delipidated flour in 6 liters of distilled water containing 5 g/l of NaCl are added in a thermostatically controlled reactor while stirring. The measured pH is adjusted continuously to 7.5.
The solution is introduced continuously for 1 hour in a closed circuit in the integral passage ultrasonic tube from example 6 (ultrasonic power: 700 Wxe2x80x94frequency: 20,000 Hz), the flow rate being 60 l/h.
A circulation of cold water allows the temperature of the solution in the vessel to be kept at about 33xc2x0 C.
Samples are taken after 15 min, 30 min, and 45 min of extraction.
After centrifugation, then filtration of the extracts over 5 xcexcm, the following results are obtained:
25.0 kg of distilled water are introduced into a reactor and the following operations are carried out in succession:
dispersing with stirring 2.5 kg of whole flour obtained by crushing whole hibiscus seeds,
adjusting the pH to 9 with NaOH 4N after 15 minutes of dispersion,
extracting with stirring for 2 hours at ambient temperature while keeping the pH at 9 by addition of NaOH 4N,
centrifuging for 10 minutes at 5,000 g,
recovering the cloudy beige supernatant liquid,
adjusting the pH to 7.5 by addition of H2SO4 4N,
centrifuging,
clarifying by renewed centrifugation,
recovering the opalescent supernatant liquid,
filtering to 0.5 xcexcm,
recovering the supernatant liquid,
spraying.
A clear beige powder can therefore be recovered with a spray yield of 62.7% weight.
In a first variation of example 8, the following operations can also be carried out:
adjusting the pH of a proportion of the extract prepared according to example 8 to 4.1 by addition of H2SO4 4N,
leaving to rest at +4xc2x0 C. (formation of a precipitatexe2x80x94about 50% of the total volume),
centrifuging to 5,000 g for 15 min,
washing the caps with distilled water at pH=4.1,
centrifuging to 5,000 g for 15 min,
collecting the precipitate,
reconstituting the precipitate in distilled water (10% of the volume prior to precipitation),
adjusting the pH to 7.5 by adding NaOH 4N while stirring,
homogenising to assist solubilisation and homogenisation,
centrifuging for 10 min at 5,000 g to eliminate the insoluble material,
spraying the protein concentrate (spray yield based on the dry extract: 82.90% by weight).
In a second variation of example 8, the following operations can be carried out:
adjusting the pH of a proportion of the extract prepared in example 8 to pH 5 by addition of H2SO4 4N,
leaving to rest for one hour at ambient temperature,
centrifuging,
collecting the precipitate,
reconstituting the precipitate in 10% of the volume prior to precipitation without carrying out the washing stage,
adjusting the pH to 7.5 by adding NaOH 4N while stirring,
homogenising to assist solubilisation and homogenisation,
centrifuging for 10 min to 5,000 g to eliminate the insoluble material,
atomising the protein concentrate.